Oil burner with rotating distributor head



Feb. 17, 1970 I M. mylar- 3,495,923

OIL BURNER WITH ROTATING DISTRIBUTOR HEAD Filed Jan. 17, 1968 4 sheets-sheet 1 Feb. I7, 1970 M. DYRE .43,495,923

OIL BURNER WITH ROTATING DISTRIBUTOR HEAD Filed Jan. 17, 1968 4 Sheets-Sheet 2 Feb. 17, E970 M. DYRE 3,495,923

OIL BURNER WITH ROTATING DISTRIBUTOR HEAR Filed Jan. 17, 1968 4 Sheets-Sheet s M. DYRE Feb. 17, 1970 y OIL BURNER WITH ROTATING DISTRIBUTOR HEAD 4 Sheets-Sheet 4 Filed Jan. 17, 1968 United States Patent O 3,495,923 OIL BURNER WITH ROTATING DISTREBUTOR HEAD Mogens Dyre, Nordborg, Denmark, assignor to Danfoss A/ S, Nordborg, Denmark, a company of Denmark Filed Jan. 17, 1968, Ser. No. 698,503 Claims priority, application Germany, Jan. 20, 1967, D 52,065 Int. Cl. F23d 1.7/04

U.S. CI. 431-116 9 Claims ABSTRACT OF THE DISCLOSURE The invention relates to oil burners of the type having a rotatable distributor head equipped with a blade arrangement which surrounds the periphery thereof.

The invention is directed in part towards particular blade arrangements wherein individual blades extend beyond the oil throwing edge of the distributor head in the direction of the flame. The invention is also directed to the providing of guide means or passages for causing hot combustion gases to recirculate back through the distributor blades.

This invention relates to an oil burner with a rotating distributor head and a blade arrangement at the outer edge thereof.

An oil burner of this type is well known in the case of which an electric motor drives a cone which has a substantially horizontal outer flange and dips into an oil supply. The oil is carried up at the outer surface of the cone and thrown off the outer edge of the flange. The flange is provided with downward-pointing blades the outer edge of which terminates with the outer edge of the flange. These blades serve as blower for the combustion air induced below the cone. Air and oil mix outside the distributor head. The combustible mixture ignites when intercepted by glowing walls.

In another known construction the distributor head is surrounded by a xed wire mesh and a pot-shaped element, in order to obtain improved admixture with the air even before the mixture is discharged into the actual combustion chamber. Due to the prolonged stay of the oil in the region of the distributor head and the potshaped element, there is a risk that the oil is heated prematurely. If this happens it may evaporate partly and form deposits on the mesh or the pot-shaped element. This risk increases the closer the ame burns to the potshaped element, heating the latter, due to the improved oil/air mixture.

In still another known construction a conical distributor head is provided, and the oil is conveyed along the upper or inner surface of this head, to be discharged to the outside. This distributor head is shuttered off from the flame chamber by a fixed cone. The fixed cone has a central aperture through which the flame gases are re-circulated, so that improved combustion can take place (blue-flame burner). The hot re-circulated gases, however, lead again to the premature heating of the oil carried on the rotating cone.

The object of the present invention is to provide an oil burner with rotating distributor head and blade arrangement which allows the most complete possible combustion, ignites easily, is easily maintained in operation and delivers a flame of improved shape while avoiding premature heating of the oil.

This object is achieved, according to the invention, in that at least parts of the blade arrangement project beyond the oil-throwing edge in the direction towards the ame.

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The ejected oil is evaporated into the air which, in this region, is still guided by the blades. In this way, a combustible oil/air mixture is obtained already in the blade region or shortly afterwards. The flame can therefore burn in a region closely adjacent the blades. The projecting parts of the blades also act as a conveyer of re-circulated hot gases. The projecting blade parts will therefore be heated by the re-circulated hot gases and the flames burning closely adjacent to them in such a degree that they start to glow. Once they glow, the fuel/air mixture will ignite directly, 'so that immediately adjacent the blade arrangement a ame ring will be maintained. This ignition process does not depend on the velocity of the oil/ air mixture or on its rate of re-ignition. Furthermore, the blade assembly is capable of imparting to the flame gases a strong drive component in circumferential direction. Thus, the ame rises along the cylindrical furnace wall in a helical path; it stays longer in the combustion chamber and makes more intimate contact with the furnace wall than in known assemblies, so that the heating power is more efliciently exploited. The remaining portions of the distributor head are largely unalected by the heat which would have an undesirable elect on the oil. It is cooled by the induced combustion air. It is only the blades or rather the blade points which are exposed to irradiation by the flame and affected by re-circulated gases.

The distributor head may also be provided with means for aiding the re-circulation of hot flame gases. This has a two-fold effect. Firstly, a more complete combustion is achieved in this way. Secondly, the outer blade portions are made to glow even more than hitherto by the hot re-circulated gases.'Constructionally, this object is achieved in that part of the wall situated on the upper or inner side of the blades leaves a gap between itself and the cone. On the side opposite the blades, re-circulated gases are thus enabled to proceed from the flame region along a very short path to the entry gap which delimits the above-mentioned wall section on one side.

Another way of boosting re-circulation consists in arranging a hollow cylinder at a distance above the distributor head which has a diameter approximately identical to that of the distributor head and is provided with ports. This cylinder makes it possible to re-circulate gases even from the upper part of the combustion chamber. It also assists the formation of a helical flame. The gases emerging from it at the bottom end are immediately deected in outward direction, towards the blade system.

Further according to the invention the distributor head may be a cone whose upper or inner side serves as an oil feed and which is provided with blades that may only project beyond its oil-throwing edge. The blades do not project into the discharged oil lm and are thus unable to impede it-an effect which would impair the conveying action.

Furthermore, the blades may extend over a considerable part of the underside of the distributor head, so as to convey cold air. In this way, intense cooling of the distributor head and an adequate conveying effect regarding the combustion air may be achieved.

The construction of the distributor head may be very simple. For example, it may consist of a single sheetmetal cone, the oil-throwing edge of which is formed by cuts adjacent the cone edge, the material of the cut portions being bent into blades integrally connected with the cone. In another construction the distributor head consists of a single sheet-metal cone to the edge of which is attached a ring-shaped blade system.

If it is feared that, due to heat conduction, an excessive amount of heat is returned to the distributor head from the glowing blades, it will be advisable to provide only paths of poor heat conduction. For example, the

ring-shaped blade system may be connected to the cone only at a few circumferential points. It is also possible to connect each blade to the cone only by means of a heat-conducting cross-section smaller than the crosssection of the blade itself.

The invention will now be explained in further detail with reference to embodiments thereof illustrated in the accompanying drawings.

FIGURE l shows a boiler with an oil burner according to the invention in diagrammatic section;

FIGURE 2 shows a second embodiment of the distributor head in side elevation;

FIGURE 3 shows the distributor head of FIGURE 2 in plan;

FIGURE 4 shows a third embodiment of the distributor head in side elevation;

FIGURE 5 shows the distributor head of FIGURE 4 in plan;

FIGURE 6 shows a fourth embodiment of the distributor head in part-sectional side elevation; and

FIGURE 7 shows the distributor head of FIGURE 6 in plan.

In the embodiment of FIGURE 1 a double-walled boiler 1 has a cylindrical combustion chamber 2. Water 3 is introduced through an inlet 4 and discharged through an outlet 5. Below, the boiler is closed by a funnel-shaped bottom 6 which is provided with an ignition device 8 in a lateral pocket 7. An electric motor 9 drives a vertical shaft 10 which, at its upper end, supports a distributor head 11. The latter consists of a sheet-metal cone 12 which, on its underside, is provided with blades 13 and has circumferential slots 15, spaced apart from the outer edge 14. The shaft 10 is hollow and, by means of its hollow, conical lower end 16, conveys oil from a reservoir 17 to the upper or inner side 18 of the cone 12. The oil is fed to the reservoir 17 through a pipe 19. The blades 13 convey the combustion air which enters through an orifice 20, provided on the underside of the bottom portion 6. Above the distributor head 11, a cylinder 21 is arranged in the combustion chamber 2 which has numerous ports 22.

While being forced out along the surface 18 of cone 12, the oil spreads in a iilm of decreasing thickness and is thrown out at the lower edge 23 of the circumferential slots and, if it has not been intercepted by one such slot 15, at the outer edge 14 of the cone 12. With a portion 24 of their longitudinal dimension the blades 13 extend beyond the oil-throwing edge 23 or 14, respectively. Thus, after having been thrown off the distributor edge, the oil reaches the region of blade portions 24 in which it is admixed with the combustion air, induced through the orifice 20, with great speed and uniformity. A helical movement is imparted to the combustible mixture by the blades 13, so that, in the annular space surrounding the cylinder 21, a helical flame moves up, making very intimate contact with the boiler wall, after the gases have ignited with the aid of device S. Due to the intimate admixture of oil and air, a flame is produced even in the region 25, immediately behind the blades 13. A certain amount of flame gases are re-circulated (see arrows 26) and reach the primary stream through the slots 15, constituting an additional source of heat for the blade portions 24. This heating efect as well as the llame in region 25 causes the blade points to glow. As a result, the flame is certain to burn immediately adjacent the blade even when the flow velocity of the oil/ air mixture exceeds the rate at which this mixture re-ignites. The glowing blade points 24 also ensure that the oil evaporates suddenly and completely in the way required for perfect combustion.

Re-circulated gases enter the primary current even directly from the flame region, through slots 15 (see the lowest arrow 26). These gases, which are particularly hot, receive excellent guidance from the wall sections 27, situated between the slots 15 and the outer edge 14 of cone 12.

The ignition device 8 may be glow-rod, for instance a silicon carbide rod which, in view of its temperaturedependent resistance, may also be used as a flame-supervising element. The size of the flame is simply regulated by varying the motor speed because, in this way, not only the oil feed but also the air feed can be inuenced. The system is suitable for all liquid fuels, for example also for fuel oil.

Although the distributor head illustrated in FIGURE 1 is of very simple construction, it may be further simplified, as becomes apparent from the embodiment illustrated in FIGURES 2 and 3. In this case, apertures 29 are provided at the upper edge of a sheet-metal cone 28, the lower edge 30' of these apertures forming the oilthrowing edge. The cut material is bent up in the shape of blades 31. These blades, therefore, project completely beyond the oil-throwing edge. It will be sufficient for their extreme points 32 to glow. Excessive heat transfer to the cone 28, and thus premature heating of the induced oil, need not be anticipated, because the blades are connected to the cone 28 only through a very small crosssection 33.

In the embodiment of FIGURES 4 and 5 an outer flange 35 is attached to a simple sheet-metal cone 34. This flange consists of a ring from which blades 36 are punched and bent out. The inner edge 37 of the resulting apertures 38 acts as the oil-throwing edge. The upper part 39 of the blades is situated above the oil-throwing edge and projects into the llame region. Also in this embodiment the blades are connected to the remaining part of the cone only through very narrow webs 40, so that the risk of an excessive heat return is eliminated.

In the embodiment of FIGURES 6 and 7 an annular blade system `43 is attached to a simple cone 41 by means of three narrow supports 42. This blade system comprises an outer ring 44 and an inner ring 45 between which the blades 46 extend. These blades are situated completely above the oil-throwing edge 47. The inner ring 45 constitutes the wall section offering improved guidance to the re-circulated gases which return to the primary stream through the gap 48. It becomes apparent from this construction that it is not the blades themselves which must be heated to glow, in order to obtain safe ignition; it will also be sufficient for the upper end of the outer ring 44 being a part of the blade system, or any other suitably arranged component of this system, to be heated by the llame itself and the re-circulated gases.

What is claimed is:

1. An oil burner and boiler assembly comprising a rotatable distributor head having an oil throwing edge, a plurality of blades attached to and circumferentially arranged relative to the periphery of said head, said blades having portions thereof extending axially beyond said oil throwing edge in the downstream direction therefrom, said distributor head having a conical portion with the apex thereof extending downwardly, an upwardly diverging frustoconically shaped wall portion surrounding said distributor head in spaced relation thereto, said blades being at least partly disposed between said distributor conical portion and said wall portion.

2. An oil burner and boiler assembly according to claim 1, said distributor head having the form of a hollow cone with the apex thereof extending downwardly, said cone having an inner conical surface upon which oil is conveyed upwardly to said oil throwing edge, said oil throwing edge being at the upper end of said cone.

3. An oil burner and boiler assembly according to claim 1 wherein said blades have substantial portions thereof extending in the downstream direction from said oil throwing edge to draw ambient air into the burner.

4. An oil burner and boiler assembly according to claim 1 wherein said distributor head comprises a hollow cone.

5. An oil burner and boiler assembly according to claim 4 wherein each said blade has only two connections.

with said cone and each said connection has a cross-sectional area which is small relative to the width of the connected blade.

6. An oil burner and boiler assembly according to claim 5 wherein said cross-sectional area of one of said connections is less than the cross-sectional area of the connected blade.

7. An oil burner and boiler assembly according to claim 1 having recirculating means for recirculating a portion of the hot ame gases through said extended -blade portions.

8. An oil burner and boiler assembly according to claim 7 having a combustion chamber above said distributor head, said recirculating means including a tubular cylindrically shaped member disposed in said combustion chamber in axial spaced alignment with said distributor head, said tubular member having openings in the wall thereof through which hot flame gases are recirculated to said distributor head.

9. An oil burner and boiler assembly comprising a rotatable distributor head having an oil throwing edge, a plurality of blades attached to and circumferentially arranged relative to the periphery of said head, said blades having portions thereof extending axially beyond said oil throwing edge in the downstream direction therefrom, said distributor head comprising a hollow cone, said cone having a plurality of circumferentially spaced openings at the upper end thereof, strut portions separating said openings which are integral parts of the cone, said oil throwing edge being segmented and formed by the lower edges of said openings, said blades being integral with said struts and extending transversely relative to said oil throwing edge.

References Cited UNITED STATES PATENTS 762,048 6/1904 Gibbs 431-168 1,442,786 1/ 1923 Scheminger 431-116 1,648,923 11/1927 Warrick 431-168 X 2,249,878 7/1941 Asbury 431-168 FOREIGN PATENTS 910,505 11/ 1962 Great Britain.

CHARLES J. MYHRE, Primary Examiner U.S. C1. X.R. 

